What an AQL inspection pass does and does not tell you

Start with the lot decision

A supplier sends an inspection report marked “AQL pass.” Before treating that as permission to ship, ask what was inspected and what the acceptance decision covers. NIST describes acceptance sampling as a way to decide whether to accept or reject a lot, rather than to estimate its exact quality.

Sampling involves risk: a plan can accept a lot of unacceptable quality or reject one of acceptable quality. The practical implication is that a pass is not a guarantee about every unit. Keep the inspection result separate from your authorized shipment-release decision.

An AQL number is not the complete plan

ASQ explains that acceptance sampling plans specify sample sizes and acceptance or non-acceptance criteria. An AQL value by itself does not identify the entire procedure used. Ask your quality owner to confirm the applicable plan, its version, inspection conditions and decision rules before the inspection.

Do not select a familiar percentage or reuse another product’s sample size simply because the supplier suggests it. Engineering and quality should define the product requirements, defect classifications and any safety-related checks. This guide does not prescribe an AQL, sample size or critical-defect policy.

Read the report against this checklist

Use this RivetBridge review checklist to make missing information visible. It is not an inspection standard or a substitute for a qualified inspector.

• Identify the purchase order, part revision, lot quantity, lot identifier and inspection date. Confirm that the report covers the goods proposed for shipment.
• Record the sampling procedure, sample size, selection method and acceptance or rejection rules. Ask how samples were selected from the identified lot.
• Match each checked characteristic to the approved requirement and inspection method. Keep cosmetic, dimensional and functional findings distinguishable.
• Record the actual findings, not just the overall rating. Check whether the report counts defects or nonconforming units and whether the plan uses that same measure.
• List unperformed tests, inaccessible goods, deviations and unresolved findings. Name the person authorized to decide each exception and the final shipment release.

Illustrative example of an incomplete pass

A fictional inspection of reader housings reports acceptable appearance and dimensions. The report does not include the specified coating-performance test, which is still pending. Purchasing should not turn the visible pass into a conclusion that every contractual requirement has been met.

Record the inspection’s limited scope and route the missing result to the quality owner. If a release depends on that test, keep the release on hold until the authorized team resolves it. The example concerns missing evidence, not an allegation about a real supplier.

Agree what happens after rejection

Before goods are inspected, agree who controls segregation, rework, sorting and any reinspection. Preserve the original failed result and identify the corrected lot and new report. Repeatedly drawing another sample until one passes is not a substitute for following the agreed sampling procedure.

Use the report to document a decision and its limits. It does not establish long-term process capability, approve an unreviewed design change or replace product-specific testing. Procurement can keep the evidence organized; your qualified quality and engineering owners decide whether it is sufficient.